Page:Popular Science Monthly Volume 92.djvu/644

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��Popular Science Monthly

��Tightening Electric Wires Under Wood Cleats

EVERYONE realizes how difficult it is to tighten a number of wires under wood cleats. Using the method shown in the illustration, it becomes a very simple

����The end or cor- ner cleats (1 and 3) are wrapped around in the direction of the pull and the cen- ter cleat (2) has half of the wires on top and half in the groove for twisting t h e'rn

��matter. The wires on the end or corner cleats of a run should be wrapped around and securely fastened to the cleats. The center cleat should have one-half of the wires on top and the other half in the groove. The cleat is then turned round and round until the wires become a tightly twisted cable. Care must be taken, however, not to stretch the wires too much as it is possible to break them. The cleat is then screwed down, holding the wires in this tight cable-like form.

��Mounting a Glass Plate Without Drilling Holes In It

THE method herein described for mounting a glass plate is much simpler than drilling, and in most cases it is to be preferred. The procedure may be utilized by the amateur for plates not having a greater diameter than 2 ft.

To mount the piate, it is necessary to place it upon marked paper that has been made for template, to enable one to determine the center. Over the center must be pasted small circles of a fibrous brown paper, one on each side of the glass. The circles must be exactly the same size as two wooden cheeks previously

��made from a cotton reel sawn in half. The paste essential for satisfactory re- sults contains the following ingredients: One teaspoonful of flour; two ounces of water; and three grains of bichromate of potash. The potash should be finely pulverized, and the ingredients must be thoroughly stirred before placing them over a flame. The mixture is brought to the boiling point in a suitable vessel. It is kept in the dark when not in use. The glass disk on which is pasted the paper circles, is placed in the sun for a few hours. This treatment insures the best result as the sun's rays set up a chemical action in the bichromate, rendering it insoluble, so that it cannot readily be detached from the plate. When dry, the wooden cheeks may be glued to the paper circles. First add a few grains of the pot- ash to the glue to prevent its being affected by dampness. A little care will secure excellent results. — Herman Neuhaus.

Changing the Tone of an Electric Bell by Sawing It

AVERY good method of changing the tone of a bell is to saw a slot A in the gong B with a hack saw; the bell will then have a tone similar to that of a cow bell. The deeper the slot, the duller the tone.

Another method of changing the sound of a bell, is by placing two bells close together so that the hammer of bell C.

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��Changing the tone of a bell by sawing a slot in the gong and a double gong ar- rangement, thus distinguishing them

on its forward stroke, strikes the gong D. On its backward stroke, T strikes the gong E on bell /•', making it sound like a tele- phone bell. When bell F is rung, the hammer only hits its own gong, giving the ordinarv sound.

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